Engine control system and method

• US 5,715,794 A
• Filed: 05/13/1996
• Issued: 02/10/1998
• Est. Priority Date: 05/12/1995
• Status: Expired due to Fees

• Current Assignee: Yamaha Hatsudoki Kabushiki Kaisha (Yamaha Corporation)
• Original Assignee: Yamaha Hatsudoki Kabushiki Kaisha (Yamaha Corporation)
• Inventors: Matsuo, Noritaka, Nakamura, Michihisa, Maebashi, Kousei
• Primary Examiner(s): Nelli, Raymond A.
• Application Number:
  US08/645,121
• Time in Patent Office: 638 Days
• Field of Search: 123/425, 123/419, 123/435, 73/115, 73/116, 73/112.3, 364/431.07
• US Class Current: 123/305
• CPC Class Codes: F02B 61/02 for driving cycles
• CPC Class Codes: F02D 21/08 the other gas being the exhaust gas of engine
• CPC Class Codes: F02D 35/023 by determining the cylinder pressure
• CPC Class Codes: F02D 41/32 of the low pressure type F02D41/3082 takes precedence
• CPC Class Codes: F02M 26/15 in relation to engine exhaust purifying apparatus
• CPC Class Codes: F02P 5/1516 with means relating to exhaust gas recirculation, e.g. turbo
• CPC Class Codes: F02P 5/153 dependent on combustion pressure
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

An engine measurement and control methodology wherein the engine combustion rate and IMEP are measured by measuring the in-cylinder pressure at specific crank angles and utilizing a basic reading of pressure in the combustion chamber when it will be near to atmospheric, and also at at least one point in time after ignition begins and before top dead center. The measured data can be employed for fine tuning the engine control to obtain optimum performance.

Claims

1. An internal combustion engine having a combustion chamber which varies cyclically in volume during engine operation from a maximum volume BDC condition and a minimum volume TDC condition, an induction system for delivering an intake charge to said combustion chamber, means for initiating combustion in said combustion chamber, and an exhaust system for discharging exhaust gases from said combustion chamber, a pressure sensor for sensing pressure in said combustion chamber at at least certain engine output shaft angles, and means for taking a pressure reading at a time between the end of the exhaust stroke and the beginning of the compression stroke when the pressure in said combustion chamber is substantially atmospheric, at an engine output shaft angle after that angle and after ignition but before TDC and at crank angles after TDC in order to measure performance characteristics of said engine.

2. An internal combustion engine as defined in claim 1, wherein the engine characteristic measured is IMEP, and IMEP is computed in accordance with the following formula:

space="preserve" listing-type="equation">IMEP=CP0+C1(P1-P0)+C2(P2-P0)+ . . . CN(PN-P0)

wherein P equals pressure measured at the designated point, C-CN are constants.

3. An internal combustion engine as defined in claim 2, wherein the engine comprises a two-cycle crankcase compression engine and the timing at which P0 is taken is no less than about 135°

before top dead center.

4. An internal combustion engine as defined in claim 2, wherein the engine is a four-cycle internal combustion engine and the timing of P0 is at approximately bottom dead center.

5. An internal combustion engine as defined in claim 2, wherein the engine ignition timing is controlled in response to the calculated IMEP.

6. An internal combustion engine as defined in claim 5, wherein the engine control is varied in response to changes of IMEP on a cycle-to-cycle basis.

7. An internal combustion engine .as defined in claim 5, wherein ignition is initiated by the firing of a spark plug.

8. An internal combustion engine as defined in claim 7, wherein the engine is provided with a fuel injector, and the timing of beginning and ending of fuel injection is controlled by the measured IMEP.

9. An internal combustion engine as defined in claim 5, wherein the engine operates on a diesel cycle, and the ignition timing is controlled by controlling the timing of direct fuel injection into the combustion chamber.

10. An internal combustion engine as defined in claim 9, wherein the duration of fuel injection is also controlled in response to the calculated IMEP.

11. An internal combustion engine as defined in claim 1, wherein the combustion rate at or near top dead center is calculated based upon using the combustion chamber pressure.

12. An internal combustion engine as defined in claim 11, wherein the engine characteristic measured is IMEP, and IMEP is computed in accordance with the following formula:

space="preserve" listing-type="equation">IMEP=CP0+C1(P1-P0)+C2(P2-P.sub.0)+ . . . CN(PN-P0)

wherein P equals pressure measured at the designated point, C-CN are constants.

13. An internal combustion engine as defined in claim 12, wherein the engine comprises a two-cycle crankcase compression engine and the timing at which P₀ is taken is no less than about 135°

before top dead center.

14. An internal combustion engine as defined in claim 12, wherein the engine is a four-cycle internal combustion engine and the timing of P₀ is at approximately bottom dead center.

15. An internal combustion engine as defined in claim 12, wherein the engine ignition timing is controlled in response to the calculated IMEP.

16. An internal combustion engine as defined in claim 15, wherein the engine control is varied in response to changes of IMEP on a cycle-to-cycle basis.

17. An internal combustion engine as defined in claim 15, wherein ignition is initiated by the firing of a spark plug.

18. An internal combustion engine as defined in claim 17, wherein the engine is provided with a fuel injector, and the timing of beginning and ending of fuel injection is controlled by the measured IMEP.

19. An internal combustion engine as defined in claim 15, wherein the engine operates on a diesel cycle, and the ignition timing is controlled by controlling the timing of direct fuel injection into the combustion chamber.

20. An internal combustion engine as defined in claim 19, wherein the duration of fuel injection is also controlled in response to the calculated IMEP.

21. A control method for an internal combustion engine having a combustion chamber which varies cyclically in volume during engine operation from a maximum, volume BDC condition and a minimum volume TDC condition, an induction system for delivering an intake charge to said combustion chamber, means for initiating combustion in said combustion chamber, and an exhaust system for discharging exhaust gases from said combustion chamber, said method comprising the steps of sensing pressure in said combustion chamber at at least certain engine output shaft angles, and taking a pressure reading at a time between the end of the exhaust stroke and the beginning of the compression stroke when the pressure in said combustion chamber is substantially atmospheric, at an engine output shaft angle after that angle and after ignition but before TDC and at crank angles after TDC in order to measure performance characteristics of said engine.

22. A control method for an internal combustion engine as defined in claim 21, wherein the engine characteristic measured is IMEP, and IMEP is computed in accordance with the following formula:

space="preserve" listing-type="equation">IMEP=CP0+C1(P1-P0)+C2(P2-P.sub.0)+ . . . CN(PN-P0)

wherein P equals pressure measured at the designated point, C-CN are constants.

23. A control method for an internal combustion engine as defined in claim 22, wherein the engine comprises a two-cycle crankcase compression engine and the timing at which P0 is taken is no less than about 135°

before top dead center.

24. A control method for an internal combustion engine as defined in claim 22, wherein the engine is a four-cycle internal combustion engine and the timing of P0 is at approximately bottom dead center.

25. A control method for an internal combustion engine as defined in claim 22, wherein the engine ignition timing is controlled in response to the calculated IMEP.

26. A control method for an internal combustion engine as defined in claim 25, wherein the engine control is varied in response to changes of IMEP on a cycle-to-cycle basis.

27. A control method for an internal combustion engine as defined in claim 25, wherein ignition is initiated by the firing of a spark plug.

28. A control method for an internal combustion engine as defined in claim 27, wherein the engine is provided with a fuel injector, and the timing of beginning and ending of fuel injection is controlled by the measured IMEP.

29. A control method for an internal combustion engine as defined in claim 25, wherein the engine operates on a diesel cycle, and the ignition timing is controlled by controlling the timing of direct fuel injection into the combustion chamber.

30. A control method for an internal combustion engine as defined in claim 29, wherein the duration of fuel injection is also controlled in response to the calculated IMEP.

31. A control method for an internal combustion engine as defined in claim 21, wherein the combustion rate at or near top dead center is calculated based upon using the combustion chamber pressure.

32. A control method for an internal combustion engine as defined in claim 31, wherein the engine characteristic measured is IMEP, and IMEP is computed in accordance with the following formula:

space="preserve" listing-type="equation">IMEP=CP0+C1(P1-P0)+C2(P2-P0)+ . . . CN(PN-P0)

wherein P equals pressure measured at the designated point, C-CN are constants.

33. A control method for an internal combustion engine as defined in claim 32, wherein the engine comprises a two-cycle crankcase compression engine and the timing at which P₀ is taken is no less than about 135°

before top dead center.

34. A control method for an internal combustion engine as defined in claim 32, wherein the engine is a four-cycle internal combustion engine and the timing of P₀ is at approximately bottom dead center.

35. A control method for an internal combustion engine as defined in claim 32, wherein the engine ignition timing is controlled in response to the calculated IMEP.

36. A control method for an internal combustion engine as defined in claim 35, wherein the engine control is varied in response to changes of IMEP on a cycle-to-cycle basis.

37. A control method for an internal combustion engine as defined in claim 35, wherein ignition is initiated by the firing of a spark plug.

38. A control method for an internal combustion engine as defined in claim 37, wherein the engine is provided with a fuel injector, and the timing of beginning and ending of fuel injection is controlled by the measured IMEP.

39. A control method for an internal combustion engine as defined in claim 35, wherein the engine operates on a diesel cycle, and the ignition timing is controlled by controlling the timing of direct fuel injection into the combustion chamber.

40. A control method for an internal combustion engine as defined in claim 39, wherein the duration of fuel injection is also controlled in response to the calculated IMEP.